1. Field of the Invention
This invention relates to apparatus to aid in the quality control testing of manufactured articles. Specifically, it relates to a device to aid in determining the finish characteristics of surfaces, such as the outside surfaces of a housing for a piece of equipment or appliance.
2. Prior Art
Monitoring the color, texture and other visual characteristics of manufactured goods has always been an important part of the manufacturing arts. Although automated methods of measuring color and texture have been developed, it is often most cost effective and more accurate to determine color and/or texture of goods through visual inspection. Problems associated with visual inspection methods generally stem from the fact that human visual perception is often uncertain and subjective. In order to overcome these problems, a variety of inspection aids and color and texture matching devices have been developed.
One perception problem associated with visual inspection is especially acute when multiple finish samples are compared to an article in succession. This problem is the inability to remember how the finish of the article being tested compared to previous samples. In addition to this memory problem, the use of multiple, separate finish samples is cumbersome and expensive because the human inspector must carry or have on hand multiple samples. These problems have been solved through combining multiple visual samples, such as colors or textures, within one convenient inspection tool. For example, U.S. Pat. No. 5,160,980 to Herpichboehm et al. discloses multiple color samples in one test strip device. U.S. Pat. No. 1,293,793 to Kaddatz discloses a device for determining the quality of milk by comparing a small sample of the milk against a plurality of possible milk color samples all deposited on a single device. U.K. Patent 351,350 discloses a device for determining the texture of sheet metal in which samples of various possible textures are arranged on a long strip.
Another perception related problem with human inspections is created because lighting, shadows and positioning can change the way a person visually perceives color and texture. This problem can be alleviated through the use of samples with a viewing hole or aperture so that the finish being inspected is seen through the aperture, and if possible, next to at least two sides of the finish sample. For example, German Patent DE-2845-237 to Rath discloses a magnetic foil sample with a viewing aperture for matching the finish color on automobiles. The article "Determination of the Skin Color with the use of Perforated Munsell Color Standards", Israel Journal Medical Science, Jan. 5, 1965, discuses improving the accuracy of visual skin color determination by making perforations in standard skin color charts.
The perception problems with visual inspections as discussed above are magnified when one is seeking to inspect the finish texture on articles that can be manufactured in different colors. In order to maintain accuracy, the samples must be arranged and used in such a way so that only one visual characteristic varies at a time. What is needed is a convenient visual inspection device that overcomes the perception and practical problems discussed above and provides various finishes in one device.